1. Field of the Invention
The present invention relates to roof ventilator in general, and more particularly, to a device and method for filtering foreign matter from external air passing through the roof ventilator.
2. Background
Roof ridge ventilators permit circulation of air through the roof of a building to decrease the temperature within the building and to allow for air circulation under the roof. Such ventilators are also desirable for the removal of moisture build-up within the enclosed cavity of the roof to prevent rotting of wooden and/or composite members. Commonly, ridged roofs will have an opening at the ridge communicating with the cavity. Ideally, the roof ridge ventilators protect the opening from the external environment while allowing air to freely circulate through the cavity.
Some currently available roof ventilators have external baffles used to deflect airflow away from the vents of the roof ventilator. That is, the external baffles do not filter air as it flows through the roof ventilator and, moreover, tend to be unsightly. In addition, other currently available ventilators use adhesives to attach various parts of the ventilator. Using adhesive tends to increase the complexity and cost of fabricating the ventilator. Moreover, adhesives tend to degrade relatively quickly over time due to the temperature cycling experienced by ventilators when installed, thereby decreasing the reliability of the ventilator.
One proposed ventilator to overcome these problems is set forth in U.S. Pat. No. 5,070,771, issued to Mankowski. Mankowski discloses a ventilator that includes a pair of flap covers hingedly connected by a hinge member integrally formed with each flap cover. Extending at an angle from the lower surface of each flap cover is a set of internal louvers (i.e., the louvers are under the covers when the ventilator is installed on a roof. Each louver includes openings extending there-through to permit the exchange of air. In addition, the louvers serve to filter the air as it flows through the ventilator. Although such a ventilator effectively vents the enclosed cavity of a roof, of course, further improvements are desirable.
One improvement that is desirable stems from recent changes in some state building codes. In response to extremely severe weather conditions, some state building codes have been amended to require that roof ventilators prevent infiltration of foreign matter into the enclosed roof cavity to which the ventilator is attached. A ventilator as disclosed in the aforementioned Mankowski patent meets such requirements for normal and even severe weather conditions. However, in extremely severe weather conditions (e.g., hurricanes), that ventilator may undesirably experience water leakage.
Thus, there exists a need for a roof ventilator that permits the free exchange of air within the roof cavity at a relatively low cost and with a high degree of performance and reliability under extreme weather conditions.
In accordance with the present invention, a roof ventilator is provided. The roof ventilator includes a cover member having a flap with a first surface over which shingles are secured and a second surface. The roof ventilator also includes a first set of louvers for deflecting airflow and reducing airflow velocity while maintaining minimum free area for air passage. Supports and a filter device are coupled to the cover member second surface. The supports extend from the second surface of the cover member flap at a height substantially equal to that of the first set of louvers to minimize interference with the first set of louvers by the supports. The filter device filters external air passing through the first set of louvers.
In accordance with other aspects of this invention, the filter device is a band of fibrous material and has a thickness that is substantially equal to the height of the supports.
In accordance with additional aspects of this invention, the filter device includes slits cut so as to be aligned with the supports when the filter device is attached to the cover member. The filter device is attached over the supports by the supports fitted into slits of the filter device.
In accordance with still yet other aspects of this invention, the roof ventilator further includes a second set of louvers located inboard of the supports. The second set of louvers have openings for further deflecting and reducing air flow velocity while maintaining a minimum free area for air passage.
A roof ventilator formed in accordance with the present invention has several advantages over roof ventilators used in the past. First, the filter device minimizes the passage of rain, insects, and dirt particles from entering the ventilated space while retaining the compact size and low cost of the roof ventilator. Second, the louvers deflect airflow while maintaining a minimum free area for air passage, such that the air flowing through the roof ventilator is substantially reduced in velocity to further limit the infiltration of foreign matter. Finally, because of its integrated design, a roof ventilator formed in accordance with the present invention can easily be manufactured and installed.